Concern about whether people have appropriate access to medical services is an important research and public policy issue. On the one hand, recent years have seen a dramatic expansion in health insurance coverage for children and pregnant women, driven in large part by fears that lack of insurance was a significant barrier to medical services for these groups. Expanding insurance coverage to the uninsured who are near elderly (ages 55-64) has also been discussed as a public policy goal. On the other hand, there is growing anxiety that recent changes in the health insurance system may limit access to appropriate medical services, even among those with insurance. The growth of managed care and the cutback in payments from Medicare and Medicaid, for example, may impede the ability of people insured through these systems to access appropriate medical care. And if these changes affect the technology that is available or norms about appropriate medical practice, they could limit access to medical care even among those with generous insurance. Understanding the factors that influence access to medical care, and how these factors are changing over time, can help determine what role public policy should play in the medical care system. The goal of this subproject is to examine the access to medical services for people with different types of insurance, and to determine how the medical care financing system affects this access. The specific aims are: 1. To present descriptive information on the uninsured. 2. To analyze the effect of an individual's insurance status on their access to appropriate medical services; and 3. To examine how the insurance environment as a whole affects access to appropriate medical services for everyone in the population.